1. Field of the Invention
The invention relates to a brush attachment for vacuum cleaners, comprising a housing consisting of a bottom part and a top part, a turbine wheel driven by a suction air stream, a brush roller driven by the turbine wheel, and a suction tube connection constructed in the form of a swivel/tilting joint. The brush roller is disposed in a brush roller chamber which has a bottom opening constructed as a suction orifice, and the turbine wheel is disposed in a turbine chamber with a connection duct of the swivel/tilting joint. The duct is pivotable about the turbine wheel.
2. The Prior Art
A brush attachment of the construction described is known, for example, from EP 0 338 760 A2. The suction air stream passes through a duct which connects the brush roller chamber to the turbine chamber, into the turbine chamber and is directed tangentially on to the turbine wheel, which is constructed as a Pelton wheel. In a construction known from DE 41 05 336 C2, a connecting duct is provided between the brush roller chamber and the turbine chamber and has an end member aligned radially to the turbine wheel. The suction air stream flows through the interior of the turbine wheel, which has blading open to the interior.
The duct leading into the turbine chamber is dependent on the type and size of the turbine wheel. The duct cross-section has to be adapted to the suction air flow and hence also to the suction capacity of the vacuum cleaner which is to be connected thereto. If the brush attachment is operated in conjunction with a vacuum cleaner the suction capacity of which differs from the values taken as a basis in designing the brush attachment, the turbine wheel does not operate with optimal efficiency.
Against this technological background, the object of the invention is to provide a brush attachment in which the incident flow is variable in a very simple manner and can be adapted to the suction capacity of the vacuum cleaner which is to be connected thereto.
To this end, in a brush attachment according to the invention, the bottom part of the housing has webs which form the back wall of the brush roller chamber and the side walls of the turbine chamber and define a flow chamber. A nozzle made as a separate part is inserted in the flow chamber and contains an incident flow duct for alignment of the suction air stream flowing against the turbine wheel, and the top part of the housing has connection webs which bear against the webs and against the top of the nozzle.
The incident flow to the turbine wheel can be changed very simply and effectively by changing the nozzle. As a result, it is possible to equip the brush attachment with different turbine wheels with optimal incident flow being ensured in each case. In particular, the duct cross-section can be adapted to the suction capacity of the vacuum cleaner which is to be connected thereto. The brush attachment can be operated with vacuum cleaners of different manufacturers with optimal turbine efficiency in each case.
According to a preferred embodiment of the invention, the nozzle rests on a base surface of the bottom part of the housing, has a wall surface which is curved in the form of an arc of a circle with respect to the turbine chamber, and contains as an incident flow duct a recess which extends as far as the base surface of the bottom part of the housing. Advantageously, the nozzle is guided laterally at the chamber-forming webs of the bottom part of the housing and is additionally fixed by positive engagement configurations on the base surface of the bottom part of the housing.
The top part of the housing can have an opening for external air and a shut-off device for metering the external air flow. In a further development according to the invention, the nozzle has an external air duct open towards the top of the nozzle and an outlet on the edge side leading to the brush roller chamber or to the incident flow duct leading into the turbine chamber. In this construction, the nozzle simultaneously forms a flow insert for guiding the external air introduced into the brush attachment. In a constructively preferred embodiment, the shut-off device is constructed as a slide which is movable in front of the nozzle outlet adjacent the wall.